The present invention relates to attachment systems for securing loaders to tractor frames and more particularly relates to a latch system for attaching the bight of a loader U-shaped brace or yoke member to the tractor front-end weight bracket or bumper.
U.S. patent application Ser. No. 08/110,444 filed 23 Aug. 1993, now U.S. Pat. No. 5,388,950 granted on 14 Feb., 1995, assigned in part to the same assignee as is the instant application, relates to a latch system for attaching a loader to a weight bracket of a tractor, the latter serving as a support for the forward end of a U-shaped brace or yoke of the loader. In this latch system, a latch operating rod extends lengthwise through a tubular, fore-and-aft extending leg of the brace or yoke and has its forward end attached to an arm fixed to one side of a latch member mounted for pivotal movement about a horizontal transverse axis between latched and unlatched positions. The geometry of the latch operating rod and arm is such as to require the rod to be shifted forwardly to move the latch to its latched position and rearwardly to move the latch to its unlatched position.
This latch operating system has been found unsatisfactory. Because of its remote location, an operator is not able to visually discern whether or not the latch is latched and the latch may, in fact, not be latched when the rod is located in its forward, latch effecting position. This may happen because the latching force is delivered to the latch with the rod in compression resulting in the relatively long rod deflecting rather than transmitting motion to the latch when the latter is obstructed from moving freely to its latched position. Also, it is possible that the latch may in some way be contacted and forced open while the lever remains in its forward, latched position.
Although latch system designs are known which utilize a rod operating in tension to effect operation of the associated latch to its latched position, these systems have enough looseness in joints or have manufacturing tolerances in the various components thereof that the position of the latch rod is an unreliable indicator of latch position.